Electrician{3 s tool for longitudinally and circumferentially cutting insulation on wire

ABSTRACT

This tool has a blade carrying assembly supporting a blade so it can be adjusted for depth of cut and can be set in one position to slit insulation lengthwise on a wire and in another position to cut the insulation around the wire. The blade has graduation marks on it so the depth of cut it is set to make can be read directly. Two wire-guiding members at opposite sides of the blade and the blade-carrying assembly are adjustable toward and away from each other to receive and hold wires of different sizes.

United States Patent 1,885,944 11/1932 Pedersen Alfred II. Powell 19321108th Ave. N.E., Bothell, Wash. 779,557

Nov. 27, 1968 May 25, 1971 Inventor Appl. No. Filed Patented ELECTRICIANS TOOL FOR LONGITUDINALLY AND CIRCUMFERENTIALLY CUTTING INSULATION ONWIRE 3 Claims, 6 Drawing Figs.

US. Cl 30/90.7

Int. Cl B26b 27/00 Field of Search 30/90. 1 90.4, 90.7, 91.1, 91.2

References Cited UNITED STATES PATENTS 1,979,487 1 1/1934 Pedersen30/90.7 2,601,724 7/1952 Jones 30/90.4X 3,091,031 1 5/1963 Grant 30/90.7

Primary Examiner-Granvi1le Y. Custer, Jr. Attorney-Fred C. MathenyABSTRACT: This tool has a blade carrying assembly supporting a blade soit can be adjusted for depth of cut and can be set in one position toslit insulation lengthwise on a wire and in another position to cut theinsulation around the wire. The blade has graduation marks on it so thedepth of cut it is set to make can be read directly. Two wire-guidingmembers at opposite sides of the blade and the blade-carrying assemblyare adjustable toward and away from each other to receive and hold wiresof different sizes.

ELECTRICIANS TOOL F OR LONGITUDINALLY AND CIRCUMFERENTIALLY CUTTINGINSULATION ON WIRE BACKGROUND OF THE INVENTION 1. Field of the InventionMy invention relates to an electrician's tool for longitudinallyslitting and circumferentially cutting the insulation on electriccircuit wire preparatory to stripping it off of the wire.

2. Description of the Prior Art In electric wiring it is common practiceto use an ordinary knife to longitudinally slit and circumferentiallycut the insulation on electric circuit wire so it can be stripped offand the wire left bare at selected locations to facilitate makingelectrical connections. Special tools have been devised for doing thiswork but, as far as known to applicant, none of these have gone intoextensive use.

SUMMARY OF THE INVENTION An object of my invention is to provide asimple and efficient electrician's tool which will save time and laborby enabling an electrician to remove insulation from wires faster andwith less effort and with greater safety to the hands than can be donewith the knives ordinarily used for this purpose.

Another object is to provide an electricians tool having a blade whichcan be quickly and easily moved rotatively between a position suitablefor longitudinal slitting and a position suitable for circumferentialcutting of the insulation on a WII'C.

Another object is to provide an electricians tool having alongitudinally adjustable blade with a sharp edge and a beveled endwhich intersects the sharp edge at an acute angle and forms a cuttingtip and having graduation marks which terminate at said sharp edge sothat, in sharpening the blade, the beveled edge can be ground tocoincide with a graduation mark at the beveled edge and the blade canthen be adjusted for any desired depth of cut by a direct reading of thegraduations thereon and without the use of any scale or measuringdevice.

Another object is to provide an electricians tool in which a bladecarrying assembly is supported from a handle by two spaced-apart springsteel plates and in which said plates terminate in edge flanges formingtool guiding members which extend beyond an end of the blade carryingmember and are adjustable toward and away from each other to bestaccommodate insulated wires of different diameters. Other objects willbe apparent from the following description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view in side elevation ofa tool embodying my invention.

F [6. 2 is an end view, on an enlarged scale, of said tool looking inthe direction indicated by line 2-2 of FIG. 1.

FIG. 3 is a fragmentary view, partly in section and partly in elevationtaken on line 3-3 of FIG. 2, a blade being shown in a different positionthan it is in FIG. 2.

FIG. 4 is a fragmentary top edge view looking in the DESCRIPTION OF THEPREFERRED EMBODIMENT This tool comprises a handle having two thin springsteel plates 11 and 12 rigidly secured to it and protruding from one endthereof in spaced-apart parallel relation. Preferably the handle 10 isfonned of strong durable plastic or similar material which is anelectric insulator. Plates 11 and 12 can be duplicates except that theyare made right and left." The plates 11 and 12 are respectivelyprovided, near their outer ends, with guide flanges 11' and 12 whichprotrude edgewise from the plates in the same direction and cooperate informing wire-guiding members. The opposed extremities of thesewireguiding members 11' and 12 are offset inwardly toward each other bybending them so as to position their wire-engaging parts at the properdistance from each other to most efficiently guide and hold the wires.Also said wire-guiding members 11 and 12 are adjustable toward and awayfrom each other by flexing them and the plates 11 and 12, as hereinaftermore fully explained.

A blade carrying assembly composed in part of two mated blocks 13 and 14is permanently secured between the plates 11 and 12 and wire-guidingmember 11' and 12'. The blocks 13 and 14 are of generally similar shapeand size and have opposed contacting faces provided with longitudinalgrooves 20,

FIG. 4. An externally cylindrical blade holder 15 is disposed within thegrooves 20. For ease and simplicity of manufacture said blade holder 15is preferably formed of two similar parts each having a flat side withinwhich is a longitudinal groove. These two parts are welded or otherwiserigidly secured together with the grooves in registration so that thegrooves cooperate in forming a guideway for a blade 21. An annularflange 17 of tapered cross secton on each end of blade holder 15 seatsin countersunk depressions 18 in each end of blocks 13 and 14. Asetscrew 22 threaded into blade holder 15 securely clamps the blade 21and holds it in any desired adjusted position. Setscrew 22 can bereached for adjustment through an opening 23 in blocks 13 and 14.

The two blocks 13 and 14 are permanently secured together by rivets 24and these assembled blocks are permanently and fixedly secured betweenthe sideplates 11 and 12 by other rivets 25. The rivets 25 urge theplates 11 and 12 and wireguiding members 11 and 12' against the sides ofthe blocks 13 and 14 but said sideplates 11 and 12 and wire-guidingmembers 11' and 12 are resilient enough so that, by application to themof outward pressure they can be caused to spring apart, as indicated bydash lines in FIG. 2, to provide enough adjustment between parts 11 and12 to take care of insulated wires of all of the difierent sizes usuallyused in electrical wiring of buildings.

For the purpose of adjustably moving the wire guiding members apart Iprovide within the blocks 13 and 14 two aligned longitudinally movablepins 26 and 27 the outer ends of which are positioned against therespective wire-guiding members 11' and 12', the pins 26 and 27 aremoved outwardly by the wedging action of a screw 28 which is threadedinto a bore 29 in the block 13 and has a tapered end 30 with which theinner ends of both of the pins 26 and 27 engage. Obviously movement ofthe screw 28 toward the pins 26 and 27 will move said pins and thewire-guiding members 11' and 12 outwardly and movement of the screw 26in the opposite direction will allow spring action to move said wireguiding members inwardly.

One edge portion of the blade 21 is beveled, preferably on both sides,to provide on said blade a fairly sharp edge 31 and the cutting end ofsaid blade, which protrudes from the blade holder 15, is beveled tointersect the edge 31 at an acute angle and form a cutting tip or point32. Graduation marks 33,

preferably one sixty-fourth of an inch apart are provided on the flatbeveled surface of at least one side of said blade and terminate at thesharp edge 31. The blade is sharpened by grinding down the beveled endof the same and, if care is exercised in the sharpening to be sure thatthe end bevel intersects The blade holder with blade clamped therein isrotatively adjustable in blocks 13 and 14 through an angle of 90 toselectively position the blade either in a plane parallel to the lengthof the tool, as shown in FIG. 3, for longitudinal cutting or slitting ofthe insulation on a wire or in a position crosswise of the length of thetool, as shown in FIG. 4, for circumferential cutting of the insulationon the wire.

The means for rotatively adjusting the blade holder 15, F IG. 6,comprises a pin 34 rigid with the upper end portion 17 of said bladeholder 15 and protruding upwardly therefrom. A sleeve 35 fits slidablyover the pin 34 and a spring 36 urges the sleeve 35 upwardly. The sleeve35 has a conical locking member 37 rigid with it and a finger piece 38of smaller diameter than the member 37 is rigid with and protrudesupwardly from said member 37. The finger piece 38 operates in an arcuateslot 40 in a cross rotate 41. Plate 41 is rigid with sideplates 11 and12. The center about which slot 41 is described is the axis of bladeholder 15. Slot 41 has enlarged openings 42 and 43 at its respectiveends. The centers of openings 42 and 43 are angularly spaced 90 and themember 37 is adapted to be seated in either of these openings to holdthe blade 15 in the position in which it is shown in FlG. 3 forlongitudinal slitting or in the position shown in FIG. 2 for forcircumferential cutting of insulation on a wire.

For longitudinal slitting of insulation on wire the blade 15 is setparallel to the length of the tool, as shown in FIG. 3, with the toolheld in one hand and the wire in the other the wire is positionedbetween the members 11' and 12', is pressed against the blade and bladeholding assembly to imbed the tip of the blade in the insulation and thetool and wire are longitudinally moved relative to each other to slitthe desired length of insulation. For circumferential slitting ofinsulation the blade 21 is positioned crosswise of the length of thetool, as shown in FIG. 2, the wire is positioned lengthwise betweenmembers 11 and 1.2 and pressed and held against the blade to imbed andhold the blade tip 32 in the insulation and the tool is then movedaround the wire in the proper direction to move the cutting edge of theblade against the insulation and make the cut.

For convenience in circumferential cutting of insulation rightandleft-hand users may find it desirable to move the tool around the wireor cable in different directions. To take care of this requirementprovision can be made for rotatively adjusting the blade 21 through anangle of l80 by using in place of plate 41 a wider plate having in it anarcuate slot similar to slot 40 except that it is slightly more than 180in extent and has three enlargements at intervals of 90, theenlargements corresponding to enlargements 42 and 43 of FIG.

Preferably a space or gap of substantial width is left between the innerend of the handle 10 and the blocks 13, 14 and, at the location of thisgap, aligned circular openings 16 are provided in the sideplates l1 and12 to receive insulation stripping mechanism of the form disclosed in mycopending Pat. application Ser. No. 642,096, now U.S. Pat. No. 3,43l,645 issued Mar. 11, 1969. Also preferably, at the location of thisgap, one or more edges of one or both of the sideplates l1 and 12 aresharpened, as indicated by numeral 19 so that at least one of thesideplates 11 or 12 can be used like a knife for cutting purposes, forinstance used to cut off pieces of insulation which have been loosenedfrom wire or cable, it being understood that this tool is equally welladapted for use on insulated wire of the single wire type or oninsulated electric cable of multiple wire type.

The foregoing description and accompanying drawings clearly disclose apreferred embodiment of my invention but it will be understood thatchanges in the same may be made.

lclaim:

1. A tool for longitudinally and circumferentially cutting insulation oncircuitwire comprising a handle; two spring steel plates rigid with saidhandle and protruding from an end of said handle; a blade-carryingassembly positioned between said two plates and supported be 0nd andadjacent to an end of the handle by said p ates; a bla e holdersupported for rotative adjustment by said blade; a blade holdersupported for rotative adjustment by said blade-carrying assemblythrough an angle of substantially about an axis generally perpendicularto the axis of the handle; a blade longitudinally adjustably supportedby said blade holder, said blade terminating at one end in a cutting tipwhich protrudes from said blade holder; two spaced-apart wire-guidingmembers integral with the outer end portions of said plates andpositioned at the sides of said blade-carrying assembly and protrudingbeyond an end of said blade-carrying assembly at opposite sides of thecutting tip of the blade, said wire-guiding members being adjustabletoward and away from each other and the terminal portions of saidwire-guiding members being offset toward each other beyond the adjacentend of the blade-carrying assembly, said cutting tip being applicable toinsulated wire guided and held between said two wire-guiding members,said blade holder providing rotative adjustment of said blade betweentwo positions in which it is respectively adapted for longitudinal andcircumferential cutting of the insulation on circuit wire disposedbetween said two wire-guiding members.

2. The tool as claimed in claim 1 in which two adjusting pins aresupported by the blade-carrying assembly with their outer endspositioned to contact the respective wire-guiding members, and a screwis threaded into said blade-carrying assembly and has a tapered partpositioned between the inner ends of sald adjusting pins adapted to movesaid pins and said wireguiding members outwardly.

3. The tool as claimed in claim 1 in which the blade is flat and has asharp edge and a beveled end which intersects the sharp edge at an acuteangle and forms a cutting tip, and in which transverse graduation marksare provided on the blade and terminate at the sharp edge of the blade,said graduation marks providing a direct reading of the distance ofprotrusion of the blade from the holder.

1. A tool for longitudinally and circumferentially cutting insulation oncircuit wire comprising a handle; two spring steel plates rigid withsaid handle and protruding from an end of said handle; a blade-carryingassembly positioned between said two plates and supported beyond andadjacent to an end of the handle by said plates; a blade holdersupported for rotative adjustment by said blade; a blade holdersupported for rotative adjustment by said blade-carrying assemblythrough an angle of substantially 90* about an axis generallyperpendicular to the axis of the handle; a blade longitudinallyadjustably supported by said blade holder, said blade terminating at oneend in a cutting tip which protrudes from said blade holder; twospaced-apart wire-guiding members integral with the outer end portionsof said plates and positioned at the sides of said blade-carryingassembly and protruding beyond an end of said blade-carrying assembly atopposite sides of the cutting tip of the blade, said wire-guidingmembers being adjustable toward and away from each other and theterminal portions of said wire-guiding members being offset toward eachother beyond the adjacent end of the blade-carrying assembly, saidcutting tip being applicable to insulated wire guided and held betweensaid two wire-guiding members, said blade holder providing rotativeadjustment of said blade between two positions in which it isrespectively adapted for longitudinal and circumferential cutting of theinsulation on circuit wire disposed between said two wire-guidingmembers.
 2. The tool as claimed in claim 1 in which two adjusting pinsare supported by the blade-carrying assembly with their outer endspositioned to contact the respective wire-guiding members, and a screwis threaded into said blade-carrying assembly and has a tapered partpositioned between the inner ends of saId adjusting pins adapted to movesaid pins and said wire-guiding members outwardly.
 3. The tool asclaimed in claim 1 in which the blade is flat and has a sharp edge and abeveled end which intersects the sharp edge at an acute angle and formsa cutting tip, and in which transverse graduation marks are provided onthe blade and terminate at the sharp edge of the blade, said graduationmarks providing a direct reading of the distance of protrusion of theblade from the holder.